The present invention relates generally to filtering systems, and more particularly is a filter module with an improved backwashing method.
In any scenario in which large amounts of water are utilized, a filtering system is necessary. Such scenarios include swimming and wading pools, fountains, fish tanks and ponds, and other aquaculture applications. The present invention was developed specifically for fish tanks and ponds, but is clearly applicable in any application requiring high volume filtering.
Most filtering systems utilize a filter tank with a filtering medium suspended in an interior of the tank. The filtering medium must be formed from a particulate material so that water can flow through the medium. Some media commonly used for filtering are diatomaceous earth, sand, gravel, and plastic pellets. The filter media remove contaminants from the water by trapping the contaminating material on the individual particles of the filter medium. After the filter system has operated for some time, there is clearly the danger of the filter being clogged by the trapped contaminants. Therefore a method of cleaning the filtering medium is required.
The method most commonly used for cleaning the filter medium in a filter tank is backwashing. Backwashing typically involves simply reversing the direction of water flow through the interior of the filter tank so that the trapped particulate matter is washed back out of the tank. One of the chief drawbacks of backwashing is that when the filter medium gets dirty, the particulate elements tend to clump together so that backwashing does not effectively remove the contaminants. This problem is recognized and addressed in the prior art.
One prior art method of attacking the aggregation of the filter media is by including a mechanical means of agitation in the tank. Two references that disclose such a scheme are the xe2x80x9cFloating Media Biofilterxe2x80x9d patents of Malone, U.S. Pat. No. 5,126,042, issued Jun. 30, 1992; and U.S. Pat. No. 5,445,740, issued Aug. 29, 1995. The devices disclosed in these references include an electric motor mounted on top of the filter tank. A vaned shaft passing through the interior of the tank rotates to stir the media.
Another method disclosed in the prior art entails an auger passing through the interior of the tank that continuously displaces the particles of the filter medium. This method is disclosed in xe2x80x9cFluid Filter Using Floating Mediaxe2x80x9d by Junius et al., U.S. Pat. No. 5,573,663, issued Nov. 12, 1996.
Accordingly, it is an object of the present invention to provide a filtering system with an improved backwashing capability.
It is a further object of the present invention to provide a means of directing water flow in the backwash operation such that the water flow breaks up clumps of particulate media.
The present invention is a filtering system with an improved backwashing capability. The system has fairly typical influent and effluent means, and uses plastic beads as the filtering medium, as do many other systems. However, the system of the present invention further includes a plurality of backwash jets that eject water under pressure at angles such that the force of the water contacting the filter beads breaks apart the beads. Separating the filter beads allows the backwash operation to provide a far more thorough cleaning of the filter tank. This leads to improved performance of the filter and extended life of the filter media.
An advantage of the present invention is that the backwash water itself serves as a means to separate the individual filter media.
Another advantage of the present invention is that no external mechanical means is required for the media separation.
A still further advantage of the present invention is that the system is simple and inexpensive to manufacture.
These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and as illustrated in the drawings.